I do own a fair bunch of MIDI controllers but I noticed that most of the time I just can't be bothered using them. I tend to program my MIDI notes and automation and in the event I need to play a short melody or drum pattern in real time I just use the Computer MIDI keyboard and edit the velocity and timing afterwards if needed. When it comes to automation, maybe it's because of my gaming background and the fact that I practically grew up with a mouse in my hand but I even find using a mouse just as good, if not better, than using a knob or a fader for MIDI CC automation (with the sole drawback that I can't operate 2 at a time).
The sometimes shaky setup of MIDI hardware, the often counter-intuitive auto-mapping of controls (and the added work of having to do it manually), the wasted desktop real estate and the fact that I constantly have to switch between my MIDI controller and my KB+mouse actually kills my workflow more than anything. Anyway, I'm pretty sure that most of the time, using MIDI controllers does more harm than good for me. I DO enjoy a minimalistic setup.
Maybe I'm the norm, maybe I'm an exception. But anyway, I have always been under the impression that most, if not almost all *serious* Live users (and computer musicians in general) use MIDI controllers in one form or another. Be it a standard chromatic keyboard, MPC style pads, some more exotic controllers or even just pots and faders for hands on control of various parameters. I'm curious if this is actually the case.